Weyl-equivariant splitting conjecture for saturated covers

Let G0\overline{G}_0 be a saturated cover, let XQ,n\mathscr{X}_{Q,n} be the relevant lattice, and let X0,Q,n\mathscr{X}_{0,Q,n} be the Weyl-stable sublattice. Let WW act by the usual Weyl action and let σX0\sigma_{\mathscr{X}_0} and σX\sigma_{\mathscr{X}} be the associated permutation representations. Weyl-equivariant splitting conjecture. There exists a WW-equivariant splitting s:XQ,nΓXQ,ns:\mathscr{X}_{Q,n}^\Gamma\to\mathscr{X}_{Q,n}. Consequently, for every zs(XQ,nΓ)z\in s(\mathscr{X}_{Q,n}^\Gamma), σX0,zσX0\sigma_{\mathscr{X}_0,z}\simeq\sigma_{\mathscr{X}_0} and σX=XQ,nΓσX0\sigma_{\mathscr{X}}=|\mathscr{X}_{Q,n}^\Gamma|\cdot\sigma_{\mathscr{X}_0}; in particular, the corresponding Whittaker dimensions satisfy

dimWhψ(πχ,S)=XQ,nΓdimWhψ(πχ0,S).\dim\operatorname{Wh}_\psi(\pi_{\overline{\overline{\overline{\overline{\chi}}}},S})=|\mathscr{X}_{Q,n}^\Gamma|\cdot\dim\operatorname{Wh}_\psi(\pi_{\overline{\overline{\overline{\overline{\chi}}}}_0,S}).

This conjecture would make the Weyl action compatible with the lattice splitting and yield the stated multiplicity formula for Whittaker models.

Sources & referencesView supporting material

Primary source

Fan Gao, Freydoon Shahidi and Dani Szpruch, “Restrictions, L-parameters, and local coefficients for genuine representations”, arXiv:2102.08859 (2021).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.